The present application relates to communication devices, communication systems incorporating such communication devices and communication methods with the possibility of an online parameter change.
Transmission of data between a transmitter and a receiver, for example wireline transmission like xDSL transmission or wireless transmission, is usually governed by a number of communication parameters which for example determine an amount of protection against various types of noise provided. In some cases, for example when noise conditions change during communication, a change of these parameters may be desirable. Online parameter change is a way of changing such communication parameters without completely stopping and newly setting up the communication connection used, for example without performing a complete handshake, initialization and training procedure performed when initially using a communication connection.
Sometimes in communication systems retransmission is used. Retransmission essentially means that if data sent from a transmitter to a receiver is not acknowledged by the receiver or not acknowledged within a predetermined time period, the data is sent again.
In such a system, when an online parameter change is to be performed, there may still be data left to be retransmitted with the old parameters.